Clashes broke out in the streets of the Bolivian capital after an opposition leader in the Senate declared herself the country’s interim president following the resignation of Evo Morales.
Jeanine Anez assumed temporary control of the Senate late on Tuesday, putting her next in line for the presidency.
Politicians of Mr Morales’s Movement for Socialism party were not present when she made the announcement.
Angry supporters of Mr Morales tried to reach the Congress building screaming, “She must quit!”
Police and soldiers fired tear gas trying to disperse the crowd.
Mr Morales, who sought to transform Bolivia as its first indigenous president, flew to exile in Mexico on Tuesday as thousands of his supporters clamoured for his return in the streets of the Bolivian capital.
Military fighter jets flew repeatedly over La Paz in a show of force that infuriated Morales loyalists who were blocked by security forces from marching to the main square.
“We’re not afraid!” shouted demonstrators, who believe the ouster of Mr Morales following massive protests was a coup as well as an act of discrimination against Bolivia’s indigenous communities.
Despite their anger, the demonstrators were peaceful.
The march followed weeks of clashes and protests against Mr Morales, who was accused by his many detractors of becoming increasingly authoritarian and rigging an election.
His resignation on Sunday led to a power vacuum in the Andean nation.
Mr Morales was met at Mexico City’s airport by Foreign Secretary Marcelo Ebrard after a flight from Bolivia on a Mexican government plane and repeated his allegations he had been forced to resign by a coup.
“The president of Mexico saved my life,” Mr Morales said, thanking President Andres Manuel Lopez Obrador for granting him asylum.
He vowed to “continue the struggle”.
Mr Ebrard said Mexican diplomats had to scramble to arrange a flight path for the plane because some nations initially closed airspace to it. The plane stopped in Paraguay to refuel.
Urged to resign by the military, Mr Morales had stepped down following widespread outrage fed by allegations of electoral fraud in the October 20 presidential election that he claimed to have won.
Resignations by all other constitutionally designated successors left unclear who would take his place and how.
Ms Anez had positioned herself to become interim president by taking temporary control of the Senate and moving into a spot to succeed to the presidency.
Mr Morales’s resignation still needed to be approved by both houses of Congress. And politicians failed to get the minimum number for an assembly session on Tuesday.
Ms Anez also needed to be approved as president of the Senate, but she said that politicians loyal to Mr Morales declined to be part of the session and that Bolivia could not be left in a power vacuum.
Mr Morales’s departure was a dramatic fall for the one-time llama shepherd from the Bolivian highlands and former coca growers’ union leader who as president helped lift millions out poverty, increased social rights and presided over nearly 14 years of stability and high economic growth in South America’s poorest country.
After Mr Morales resigned, angry supporters set barricades ablaze to close some roads leading to the country’s main airport on Monday, while his foes blocked most of the streets leading to the capital’s main square in front of Congress and the presidential palace.
Street tensions ebbed after General Williams Kaliman, chief of the armed forces, announced a joint police-military operation in a television address.
He said the hope was to “avoid bloodshed and mourning of the Bolivian family,” and he urged Bolivians to help restore peace